The UK's first-ever prime ministerial debate was broadcast on British television last night. The debate was between the leaders of the three main parties - Gordon Brown, David Cameron and Nick Clegg and follows a tradition that was first started in the US 50 years ago. So in one of the tightest British elections of recent times did this political showdown actually change anything? Sir David talks to the American pollster Frank Luntz. Plus, Poland's president, Lech Kacyzinski, the first lady and dozens of the country's military and political elite were killed when their plane crashed in Russia last Saturday. Kacyzinski was on his way to commemorate another Polish tragedy, the Katyn massacre of 1940, where 22,000 Poles were executed by Soviet troops. Sir David talks to one of Britain's leading historians, Professor Norman Davies, about this event.